A standard helmet such as worn by a motorcyclist, in particular a police officer, has a rigid head piece that fits over the wearer's head and that is formed with a forwardly open cutout aligned with the wearer's face. For maximum security it is standard in design to form the helmet with a rigid chin guard or protector that bridges the sides of the helmet under the face cutout and that serves to protect the wearer's mouth and jaw region. In addition a transparent lens or visor is provided to cover the face cutout, in particular on a helmet used for security or riot-control work.
In helmets with integral chin guards it is necessary that the chin guard be spaced far enough forward to provide clearance and allow the wearer to doff and don the helmet. Thus such a helmet must also be provided with a separate chin strap that passes under the wearer's jaw and holds the helmet in place. Another disadvantage of the known helmets is that the wearer cannot conveniently talk to someone with it on, as the chin guard blocks his or her mouth, so that the helmet must be taken off when dealing with a person face-to-face.